Chamaecrista lineata var. pinoi

  • Title

    Chamaecrista lineata var. pinoi

  • Authors

    Howard S. Irwin, Rupert C. Barneby

  • Scientific Name

    Chamaecrista lineata var. pinoi (H.S.Irwin & Barneby) Britton & Rose

  • Description

    40f. Chamaecrista lineata (Swartz) Greene var. pinoi (Britton & Rose) Irwin & Barneby, stat. nov. Ch. pinoi Britton & Rose, N. Amer. Fl. 23(5): 283. 1930.—"Between Jalisco and Tuxtla Gutierrez, Chiapas, 1923, Purpus 9384."—Holotypus, collected VIII (fl), US! isotypus, NY!—Cassia pinoi (Britton & Rose) Lundell, Phytologia 1: 215. 1937.

    Frutescent, ultimately fruticose, apparently erect, at anthesis 3—9(—?) dm, the slender, sometimes flexuously zigzag trunks brown or longitudinally striped, the hornotinous branchlets and foliage pilosulous throughout with fine incumbent, spreading-incurved, and (especially lf-stalks and pedicels) some few longer spreading hairs to 0.3-0.8 mm, the dull, pallidly olivaceous concolorous lfts pilosulous on both faces but sometimes more thinly so above; stipules 3-7 x 0.7-1.1 mm, 5-7-nerved; major lvs up to 2—4 cm; gland 0.2-0.3 diam, minutely stipitate, in profile squatly tack-shaped 0.25-0.4 mm tall, mostly a trifle (±0.1) mm longer than diam of head; lfts of major lvs up to 6-8 pairs, oblong-obovate or the short distal pair obliquely obovate, all very obtuse mucronulate, up to 6.5-11 x 3-4.5 mm, the slightly displaced midrib giving rise on each side to 2-4 major with fainter intercalary secondaries, the venation subequally prominulous on both faces; peduncles axillary 1-fld; pedicels 13-20 mm; sepals up to 7.5-9 mm; long adaxial petal 10.5-12.5 mm, the cucullus exceptionally ample and up to 14-15 mm; ovules 8-9; pod (little known) ±30-35 x 4.5 mm, incurved-pilosulous and sometimes in addition remotely pilose.—Collections: 3.

    Habitat not recorded, but to be expected in xeromorphic, drought-deciduous scrub-forest, ±70-600 m, local, known only from three stations on the Pacific slope of Istmo de Tehuántepec in s.-e. Oaxaca (Cerro S. Pedro; Ixtepec) and in adjoining s.-w. Chiapas (Jalisco).—Fl. VII-X (and probably later).

    Britton & Rose presented Ch. pinoi as kindred to Ch. greggii, gravely different in the leaflet venation, obtuse sepals and subglobose flower buds, and separated these collectively from Ch. lineata and its West Indian relatives in geographical terms alone. They described Ch. pinoi as a treelet 3.5—4 m tall, but there are no data directly associated with the type-collection to indicate that such was the case. The arborescent character is derived from a letter (NY, copy) written on February 24, 1925 in the village of Jalisco, Chiapas, in which Carl Anton Purpus describes to J. N. Rose his return to the original locality of Ch. pinoi, discovered in August two years previously. Here Purpus describes the plant as a small tree with "flowers hanging down on the stem," but in February only few of these present with old leaves, pods, and ripe seeds. These were said to have been collected, but there is no mention of fruit in the protologue and we have found no Purpus collection at US or elsewhere that we can identify as such. An arborescent habit is certainly not impossible in Chamaecrista, but the two collections of Ch. pinoi known to us from Oaxaca, both close matches for the holotypus in details of foliage, gland and pubescence, are noted by the collectors as only one or three feet tall. The treelet habit is therefore not characteristic, and the idea may have been introduced by some unexplained error on the part of Purpus. Disregarding this false, or if not false inconstant character of stature, we find scarcely any tangible quality of habit or foliage by which Ch. pinoi can be separated from loosely pubescent Ch. lineata, even though we have found no particular West Indian specimen that matches the Mexican material at all points. The peduncle of Ch. pinoi is exactly axillary, but so is that of some Bahaman var. lineata. Only the proportions of the perianth seem a little different, the longest petal in var. lineata being ordinarily the adaxial one paired with the cucullus, whereas in Ch. pinoi it is the cucullus itself. It is on this precarious morphological basis, reinforced by disjunct dispersal, that we provisionally maintain var. pinoi at varietal rank.

    The person commemorated by the epithet, which Purpus at one place in the cited letter spells "del Pinoi," is unknown to us.